Although I enjoyed this novella very much, because it deals with one of my favorite characters ever, I would call it almost not a story at all, or more of a bridge story. It does have a plot, but that plot doesn't follow the typical curve of what we usually think of as a story plot. There are two stories in one, in a sense.
The first part deals with an incident that happens in London involving an electric eel and a duel. The second part takes place in Canada, and contains a fictionalized recounting of General Wolfe's attack on the fortress at Quebec, in which he won Canada for England from the French.
But of course the character Lord John Grey's story line within the historical backdrop is more personal. The second part of the story, in which he travels to Canada along with his trusty valet Tom Byrd, mainly involves Grey's reunion with Captain Malcolm Stubbs (married to Lord John's cousin Olivia), and - the main reason for the trip - Grey's old friend named Charles Carruthers, who is awaiting court-marshal in Canada for "failure to suppress a mutiny" and needs Lord John to be a character witness.
Of course, being Lord John, he is immediately thrown into scrapes, conflicts, and adventures, wherever he goes. Molly (the historical term for a gay man) that he is, he even finds time to indulge in his attraction to an Indian scout named Manoke. But in this novella, nearly every story line seems to be quickly resolved rather than forming a sustained plot curve, except for the story concerning Carruthers, which isn't really resolved at all. Again, I think of this as a bridge story, because the events in it come up for discussion in the next full length novel, The Scottish Prisoner. In fact, the Charles Carruthers court-marshal is the impetus for that entire story. Although it's covered enough in The Scottish Prisoner for that book to be a standalone, I still would have preferred to read this story first, and strongly recommend reading this novella before reading that novel. As a writer, I can see plainly why it would not have served to include these events in The Scottish Prisoner, that they really needed to be covered in this separate novella. It's just kind of unusual, but still highly recommended.